Device for fashioning a flange on a wall, and more particularly on a pipe wall

ABSTRACT

A device for fashioning a flange on the wall of a pipe, comprising a forming tool which passes through a hole previously drilled through the pipe wall and is possessed of rotation about and translation along an axis merging with the geometrical axis of said hole. The forming tool includes two forming members which are symmetrical in relation to said rotation/translation axis. Adjustment means allow varying the working diameter of the tool.

1 United States Patent 1191 1111 3,817,071 Chalvignac June 18, 1974 [5 DEVICE FOR FASHIONING A FLANGE ON 3,050,102 8/1962 Hock 72/120 A WALL AND MORE PARTICULARLY O 3,131,746 5/1964 Streeter 1 72/1 12 A PIPE VVALL 3,468,147 9/1969 Davies 29/157 3,592.038 7/1971 Larikka .1 72/112 [75] Inventor: Jean Ferdinand Chalvignac, Reims,

France P E LO llAL rlmary .tammerwe arson [73] Asslgnee: VIRAX Pans France Attorney, Agent, or FirmA. W. Breiner [22] Filed: Mar. 19, 1973 [21] Appl. No.: 342,375

[57] ABSTRACT [30] Foreign Application Priority Data A device for fashioning a flange on the wall of a pipe, Mar. 20, 1972 France 72.10577 comprising a forming tool which passes through a hole previously drilled through the pipe wall and is pos- U.S. Cl-

T sessed of rotation about and translation along an axis ll'lt. merging the geomgtrical axis of aid hole The Field of Search 29/157 T; 72/1 12, 120, forming tool includes two forming members which are 72/370 symmetrical in relation to said rotation/translation axis. Adjustment means allow varying the working di- [56] References Cited ameter f the L UNITED STATES PATENTS 656,425 8/1900 Schilling et a1. 72/120 5 Claims, 8 Drawing Figures PATENTEDJUM 1a 1914 SHEU 1. 4

7 23a 23m 2415 I25 DEVICE FOR FASHIONING A FLANGE ON A WALL, AND MORE PARTICULARLY ON A PIPE WALL The present invention relates to a device for fashioning a flange on a wall which separates an inner space from an outer space and which has been previously drilled with a hole which communicates said inner space with said outer space. The invention is more particularly though not exclusively applicable to the fash ioning of a flange on the wall of a pipe made of metal or plastics.

The fashioning of a flange is an operation to which recourse is frequently hadwhen it is required to make a branch connection on a tube having a relatively thin and deformable wall. The procedure in such cases is to first form, through the pipe wall, at the desired location, a hole having a small diameter in relation to the diameter of the required branch connection. A suitable fashioning tool is then inserted through this hole into the pipe and has imparted to it a compound motion of rotation about the geometrical axis of the hole and of linear translation directed from the interior to the exterior of the pipe. By means of this tool, the wall portion surrounding the hole is gradually thrust outwardsfrom the pipe, thereby enlarging the hole up to the diameter required for the branch connection while at the same time forming around it a cylindrical flange, and the smaller the initial diameter of the hole the greaterwill be the height of this flange.

In what follows, when the fashioning tool is in its working position, the term tool working radius will refer to the distance between the rotation axis of the tool and the point thereof in contact with the inner surface of the pipe wall. Similarly, the term tool working diameter" is to be understood as being equal to twice the working radius of the tool.

Already known are a variety of devices for performing. the above-described operation, most notably on thin-walled pipes used for transmitting and distributing liquids or gases. However, such devices have a number of disadvantagesstemming directly or indirectly from the fact that prior art fashioning tools have a nonadjustable working radius or diameter.

A first disadvantage resides in the fact that such a fashioning tool with a non-adjustable working radius can be used to form onlya single flange diameter. in consequence, a specific fashioning tool must be provided for each branch diameter required, which is somewhat uneconomical.

A second disadvantage, which is bound up directly with the first, stems from the fact that in the case of a fashioning tool of non-adjustable working radius, the effective working radius gradually decreases as a result of tool wear; consequently, the flange diameters produced with such a tool will likewise gradually decrease, soon making the tool useless.

A third disadvantage arises from the fact that prior art fashioning tools of non-adjustable working radius are asymmetrically configured with respect to their rotation axis-in any event in the case of large-workingradius tools intended for fashioning deep flanges of large diameter, since a symmetrically configured forming tool havinga large non-adjustable working radius could not be inserted into the pipe through an initial small-diameter hole drilled through the pipe wall.

The effect of said asymmetrical configuration during the flange forming operation is to generate large noncompensated forces in a direction parallel to the longitudinal axis-of the pipe that tend to entrain the latter in one direction and the other alternately. This makes it necessary to securely restrain the pipe during the fashioning operation in order to oppose these longitudinal forces. This can be accomplished either by means of an arrangement of clamps or shells with an inner diameter exactly matching the outer diameter of the pipe to be restrained, or. by means of an adjustable vice. The former solution callsfor a set of jaws or shells for each pipe diameter involved, which, in view of the wide diversity of commercially available piping, is uneconomical. In the alternative solution, the use of a vice or like clamping device could crush the pipe; to avoid this the pipe would not have to be overtightened, but in that case it might be insecurely restrained and the fashioning operation could be compromised as a result. Further, the time needed to clamp the pipe before fashioning the flange increases the production cost of the flange to a by no means negligible extent.

While it is admittedly known to use forming tools having a symmetrical configuration with respect to their rotation axis (an example being ball-type forming tools), such tools cannot be used to obtain flanges which are at once deep and of large diameter.

It is the general object of the present invention to at least partly overcome the aforementioned disadvantages and to accordingly provide a. forming tool of adjustable working radius having a symmetrical configuration in relation to its rotation axis, that allows fashioning flanges which are at once deep and of large diameter and that can be used without the need to em ploy shells or a vice to restrain the pipe. The present invention is based on a known device comprising, in combination, a forming tool having a portion adapted to be inserted from the outer space into the inner space through the hole previously drilled in the pipe wall, said tool being rotatable about a geometrical axis substantially merging with the geometrical axis of said hole and being furthermore translatable linearly along the same axis; a tool-holder; means for attaching said tool to the tool-holder; and means for rotating said tool-holder about, and translating it linearly along, said rotation/translation axis.

A fashioning device according to this invention is characterized in that said forming tool includes two distinct forming members arranged symmetrically in relation to the rotation/translation axis of the tool; in that said means for attaching the tool to the tool-holder include two hinge pins respectively associated to said two forming members and by means of which each of these two forming members are hingedly connected to said tool-holder, said two hinge pins being at once perpendicular to said rotation/translation axis and positioned symmetrically in relation thereto; and in that adjustable means are provided for simultaneously pivoting said two forming members, each about its own hinge pin, thereby to simultaneously vary the angular positions of said two forming members in relation to said toolholder.

in accordance with one possible: embodiment of the invention, the forming tool likewise includes a slide which is connected to the two aforesaid forming members and which is positioned coaxially with the rotation/translation axis of the tool and is translatable in a straight line along that axis.

For the purpose of causing simultaneous pivoting of the two forming members, the invention preferably provides for a control rod positioned coaxially with said rotation/translation axis and capable of being actuated externally of the device, for instance by means of a control rod. This control rod is connected to said slide through an adjustable threaded link and is capable of being rotated about said rotation/translation axis with respect to the tool-holder and of being translated in a straight line therealong. As will be explained hereinafter, the first of these two motions permits continuous adjustment of the working radius of the forming tool, while the second of these motions permits insertion into the space within the pipe of the tool after the latter has had its working radius adjusted thus beforehand.

Further particularities and advantages of the invention will become apparent from the description which follows with reference to the accompanying nonlimitative exemplary drawings and which will give a clear understanding of how the invention can be carried into practice.

In the drawings:

FIG. 1 schematically illustrates the fashioning of a branch connection on a pipe subsequent to formation of a flange on the wall thereof;

FIG. 2 is a schematic portrayal, in cross-section to the longitudinal axis of the pipe, of a flange fashioning device according to the invention;

FIG. 3 is a sectional view, through the line III-III, of the fashioning device shown in FIG. 2;

FIG. 4 is a schematic view, in cross-section to the longitudinal axis of the pipe, showing a symmetrically configured forming tool with adjustable working radius forming part of the fashioning device shown in FIG. 2, said tool being in its minimum-working-diameter configuration;

FIG. 5 is a schematic portrayal similar to FIG. 4 but in which the forming tool is shown in its maximum-working-diameter configuration;

FIG. 6 is a similar showing to FIG. 2, illustrating an alternative embodiment of said fashioning device;

FIG. 7 is a perspective showing of the forming tool which forms part of the fashioning device shown in FIG. 6; and

FIG. 8 is a perspective showing of two symmetrical forming members which form part of the forming tool shown in FIG. 7.

Reference is first had to FIG. 1, in which reference numeral 1 designates a wallin this instance the wall of a pipe 2 of diameter d-separating an inner space 3 from an outer space 4. Fashioned on wall 1 is a flange 5 for connecting a branch pipe 6 to pipe 2. On the right-hand side of FIG. 1 is shown a small-diameter hole 7 which has been drilled beforehand through wall 1 and which is used to initiate the fashioning of a further flange 8 by means of the fashioning device to be described hereinbelow.

Reference is next had to FIG. 2 for showing of a flange fashioning device according to the invention.

Such device basically includes a forming tool 9 which is rotatable about a geometrical axis YY merging substantially with the geometrical axis of hole 7 and which is additionally translatable linearly along said axis. Through the agency of attachment means to be described hereinafter, tool 9 is connected to a toolholder 10 coaxial with said rotation/translation axis YY and capable of being rotated about and linearly translated therealong.

Tool 9 and tool-holder 10 are movable within a cylindrical casing 11 which is closed at one end by a cover 12 having an opening 13 therein.

Tool-holder 10 is formed by a first portion 14 having an outer diameter substantially equal to the inner diameter of casing 11 and a second portion 15 of smaller diameter. The first tool-holder portion 14 is formed with a diametrical slot 16 (see FIGS. 2 and 3) which extends up to its free end. The second tool-holder portion 15 is formed at one end with a bore 17 and at its other end with a bore 18 which communicates with bore 17 through a bore 19 of smaller section. Bore 17 further communicates with diametrical slot 16. Bores l7, l8 and 19 are coaxial with the rotation/translation axis YY of forming tool 9.

Forming tool 9 comprises two distinct forming members 9a, 9b (for greater clarity in the drawing, only one is shown complete in FIG. 2) and a slide 20, one end of which is fast with a clevis 21. The two forming members 9a, 9b are arranged symmetrically in relation to rotation/translation axis Y-Y. Each includes an active portion or finger 22a (22b) integral with a supporting portion or finger-support 23a (23b) in which is formed an inclined oblong window 24a (24b). One edge of finger-support 23a (23b) is designated 23 ax (23 bx).

The two finger-supports 23a and 23b are pivotally connected to tool-holder 10 by means of hinge pins 25a and 25b respectively carried by tool-holder portion 14 and extending through slot 16. The two hinge pins 25a, 25b are perpendicular to the rotation/translation axis YY of tool 9 and are symmetrically positioned with respect thereto.

Each of the two forming fingers 22a and 22b is shaped substantially as the arc of a circle having its centre on or near the corresponding hinge pins 25a and 25b.

The two forming members 9a and 9b and slide 20 are interconnected by means of a pivot 26 which is parallel to the two hinge pins 25a, 25b and which extends through the two branches of clevis 21 and through the two finger-supports 23a and 23b, by way of the two oblong windows 24a, 24b.

Slide 20 is positioned coaxially with the rotation/- translation axis YY of tool 9 and is linearly translatable along that axis through bore 17. Slide 20 and the two forming members 9a and 9b articulated thereto by means of pivot 26 are so arranged that when the slide translates through bore 17 the two forming members 9a, 9b pivot simultaneously within diametrical slot 16, each about its hinge pin 25a (25b), whereby the angular position of said forming members in relation to the tool-holder 10 is caused to vary.

FIGS. 4 and 5 illustrate the effects of this pivotal motion.

FIG. 4 shows one of the limit angular positions reached by the two forming members 9a, 9b. In this position, the two active portions or fingers 22a or 22b are almost fully retracted into casing 11, with only the free ends of the fingers protruding through the opening 13 therein. The working diameter of tool 9, as defined precedingly, is then at a minimum value D permitting simultaneous insertion of the two fingers 22a, 22b into the inner space 3 of pipe 2, through the hole 7 previously drilled into the wall 1 of said pipe. In this position, the edges 230x, 23bit, of finger supports 23a and 23b respectively, are preferably at the limit of their travel in abutment against tool-holder 1.4, as shown in dashlines in FIG. 2.

FIG. 5 shows the other limit angular position reached by the two forming members 9a, 9b. In this position, the two active portions or fingers 22a, 22b are fully extended within inner space 3 of pipe 2, and the working diameter of tool 9 is at a maximum value Dma,r less than or at most equal to the pipe diameter d.

Thus, to each angular position of the two forming members 90, 912 included between the two aforesaid limit positions there corresponds a value D for the working diameter of tool 9 that lies between D and unn'- A control rod 30 allows of linearly translating the slide 20 and hence of continuously modifying the angular position of the two forming members 9a and 9b. Control rod 30 is arranged coaxially with the rotation/- translation axis Y'( of tool 9, through the three bores 17, 18, 19 in the tool-holder, and is at once rotatable about axis Y-Y linearly translatable therealong with respect to the tool-holder.

Control rod 30 has one of its ends fast with a threaded member such as a screw 31 engaging with an associated threaded member such as a nut 32 fast with slide 20. Thus any movement of control rod 30 relative to tool-holder 10, whether in rotation about or linear translation along the axis YY, causes slide 20 to be translated in a straight line along that axis with respect to tool-holder l0, and consequently the two forming members 9a, 9b to pivot about their respective hinge pins 25a, 25b.

At its other end, control rod 30 is extended by a sleeve 33 coaxial therewith and rigidly secured thereto through the agency of screws, for instance. Sleeve 33 protrudes from tool-holder and is topped by an actuating knob 34 which is driven or screwed onto it and is accessible from outside the device. Hence any rotation or translation motion imparted to control knob 34 produces a corresponding rotation or translation of control rod 30.

At one of its ends, sleeve 33 forms an abutment rigid with control rod 30, and a compression spring 35 has one end reacting thereagainst and its other end in pressure contact with the bottom of the bore 18 formed in tool-holder 10. Spring 35 consequently tends to translate control rod 30 and slide 20 in a straight line along axis Y-Y, in a direction such as to cause thetwo forming members 9a, 9b to occupy their limit angular position shown in FIG. 4, in which the working diameter of forming tool 9 assumes its minimum value D Formed over this periphery of bore 18 is an annular groove 36 which is coaxial with the rotation/translation axis Y-Y of tool 9 and into which can engage locking balls 37 carried by tubular sleeve 33.

The balls 37 are part of a locking mechanism for latching the control rod 30 in a predetermined and invariable axial position in relation to tool-holder 10. This locking mechanism prevents control rod 30 from translating along axis Y-Y beyond said latching position but does not prevent if from rotating about said axis.

The locking mechanism for control rod 30 further includes a thrust member 38 which, in the latching position shown in FIG. 2, thrusts the balls 37 into annular groove 36. Thrust member 38 is fast with a rod 39 which is movable through the bore of sleeve 33. This rod is formed with a collar 4% and is extended by a pushbutton 41 coaxial with control knob 34 and accessible from outside the device. A spring 42, one end of which bears against collar 40 and the other against an abutment fast with sleeve 33, urges thrust member 38 toward its latching position. When pushbutton 41 is depressed, thrust member 38 ceases to be in contact with the balls 37, so that the. latter emerge from annular groove 36. Thus pushbutton 41 acts as an unlocking member for releasing the control rod 30.

Means are provided for rotating the tool-holder 10 about the axis Y-Y and for translating it in a straight line therealong. In the example shown in the drawings, said means include a driving handle 43 angularly rigid with tool-holder 10 and two mutually engaging threaded members, one of which is formed by a screw 44 fast with tool-holder portion 15 while the other includes a nut 45 made angularly rigid with the casing 11 by means, say, of a retractable linchpin 46. Preferably, the threads on the two members 44 and 45 are finepitched in order to reduce the force to be exerted on handle 43. Obviously, the handle 43 could be replaced by any convenient driving means such as an electric motor.

At its end proximate the opening 13, casing 11 carries two abutment members or pegs 47, 48 which flank the pipe 2 to be worked and are intended to prevent the latter from rotating about rotation/translation axis Y'-Y during the flange fashioning operation.

The theory of operation of a flange fashioning device according to this invention is as follows:

The first step is to adjust the working diameter D of forming tool 9 according to the flange diameter to be obtained. To this end, control rod! 30 is rotated about axis Y'-Y by means of control knob 34, thereby causing it to be translated therealong together with slide 20. This adjustment is possible irrespective of whether or not the control rod 30 is locked against translation by locking mechanism 36, 37, 38. In order to facilitate preselection of the working diameter D of tool 9, control knob 34 may be provided with a pointer which moves before graduation marks on. tool-holder 10. The tools working diameter thus remains set and visible at all times and can be adjusted whenever required during the work.

The next step is to depress the unlatching pushbutton 41 in order to release control rod 30 (if this has not already been done), whereby forming tool 9 moves into its retracted position, shown in FIG. 4, responsively to spring 35. Being in its minimum-working-diameter configuration D,,,,,,, the tool 9 with the two symmetrical forming fingers 22a, 22b can penetrate into the hole 7 previously drilled through the wall 1 of pipe 2.

The knob 34 is then moved axially against the countering spring 35 until the locking balls 37 re-engage into annular groove 36 and control rod 30 is thus latched anew against axial translation. At the end of this operation, forming tool 9'is in the deployed position shown in FIG. 5 in which the two symmetrical forming fingers 22a, 22b splay out into their preselected position. In the example shown in FIG. 5, it has been assumed that the working diameter of tool 9 (22a, 22b) is equal to the maximum-working-diameter D thereof, which is in turn substantially equal to the pipe diameter d.

The flange fashioning operation can then begin. The handle 43 is accordingly used to impart rotation to tool-holder 10 about axis Y-Y. By reason of the nut 45 being fast with casing 11, the tool-holder is simultaneously constrained to translate linearly, along the same axis, outwardly inside the pipe. Forming tool 9 (and specifically its active portion consisting of the two forming fingers 22a, 22b) describes exactly the same motion, so that fingers 22a, 22b are fetched into contact with the pipe portion to be deformed and the flange 8 is gradually formed by the process illustrated schematically in FIG. 1. It is to be noted that the portion of finger 22a (22b) in contact with the pipe is devoid of sharp edges.

The cover 12 fast with the casing 11 prevents pipe 2 from being drawn thereinto during the fashioning operation. With regard to the abutment members or pegs 47, 48, their function as already stated is to prevent the pipe from rotating about axis YY. It should be pointed out that by reason of the symmetrical arrangement of the two forming fingers 22a, 22b, the pipe 2 is subjected to no significant forces acting along its longitudinal axis, making it unnecessary to resort to a vice or to a set of shells in order to restrain the pipe longitudinally.

By operating linchpin 46 it is possible to momentarily release nut 45 from casing 11 and to allow it to rotate freely inrelation thereto about the axis Y'-Y. Under such conditions, tool-holder l and hence tool 9 will be possessed solely of rotating motion about axis YY. This feature is useful when it is required to smooth the flange or else to heat the pipe material in order to facilitate the flange fashioning operation, especially in the case of pipes made of plastics.

A flange fashioning device according to this invention offers, inter alia, the following advantages:

It enables one end and the same tool to be used to fashion flanges over a wide range of diameters and depths. The control knob permits accurate adjustment of the selected diameter.

It allows compensating for tool wear, since the tool working diameter is adjustable. This is effected very simply by altering the position of the setting pointer on control knob 34.

It enables flanges of great depth to be formed. As shown in FIG. 1, this insures generous overlap between the flange 5 and the pipe 6 inserted into it, thereby improving both the sealing qualities and the mechanical strength of the joint between the two pipes 2 and 6.

It obviates the need for vices or special shells for longitudinally restraining the pipe being fashioned.

FIGS. 6 through 8 illustrate an alternative embodiment of the invention. In these figures, like parts are designated by like reference numerals.

A first difference relates to the driving handle 43, which in this alternative embodiment is equipped with a unidirectional coupling device 50-of the ratchet type, for exampleenabling it to be rotated backwards in cases where there is only limited room for performing the fashioning operation.

A further difference resides in the provision of a trigger 51 for operating the linchpin 46. Trigger 51 is piv- 6 Nut is supported by casing 11 on an anti-friction bearing 54, for instance of the ball-bearing type. To release nut 45, i.e. to allow it to rotate freely relative to casing 11, all that is necessary is to squeeze the trigger 51. The latter can be maintained in the released position by a locking spring 55 which can be rendered inoperative by an unlocking button 56.

Still another difference relates to the means for connecting the two forming members 9a, 9b to tool-holder 10. In this instance, each of these two members includes, as a bearing for the corresponding hinge pin 25a (25b), a lodging a (60b) formed with an aperture 61a (61b) over part of its periphery. This aperture makes it possible, by a hooking motion, to engage said forming members over said hinge pin, or to release it therefrom by an unhooking motion. This feature is particularly useful because it facilitates dismantling of the forming tool 9 (9a, 9b, 20) to allow a standard replacement item to be substituted in the event of accidental damage to the tool. Such removal can be effected simply by fully unscrewing screw 31 from nut 32.

Yet another difference resides in the abutment members or pegs 47, 48, which in this alternative embodiment are carried by an orientable head 62 which caps the casing 11 and which can be latched in the selected position by means of a locking button 63. This feature offers the advantage of enabling the operator to select the best or most comfortable working position, in view of the fact that in cases where the pipe to be worked is already in position-along a wall for instance-its location and/or orientation are imposed once and for all and can no longer be modified.

It goes without saying that changes and substitutions of parts may be made in the specific forms of embodi ment described hereinabove, without departing from the scope of the invention.

I claim:

1. A device for fashioning a flange on a wall, said wall separating an inner space from an outer space and being beforehand formed with a hole for communicating said inner space with said outer space, said device comprising, in combination a forming tool having an active portion capable of being inserted from said outer space into said inner space through said hole, said tool being rotatable about a geometrical axis substantially merging with the geometrical axis of said hole and being furthermore translatable linearly along the same axis, said forming tool comprising two distinct forming members symmetrically positioned in relation to said tool rotation/translation axis, a slide slidable coaxially with said tool rotation/translation axis, and attachment means for attaching said two forming members to said slide;

a tool-holder movable coaxially with said rotation/- translation axis;

attachment means for attaching said tool to said toolholder and comprising two hinge pins respectively associated to said two forming members and through the agency of which each of said two forming members is hingedly connected to said toolholder, said two hinge pins being perpendicular to said rotation/translation axis and symmetrically positioned in relation thereto;

means for imparting to said tool-holder rotation about and linear translation along said rotation/- translation axis;

and adjustable means for rectilinearly translating said slide with respect to said tool-holder along the direction of said rotation/translation axis whereby to simultaneously pivot said two forming members about their respective hinge pins and thereby simultaneously vary the angular positions of said two forming members with respect to said tool-holder, said adjustable means including, in combination a control rod coaxial with said tool rotation/translation axis; two mutually engaging threaded members, one of which is fast with said control rod and the other with said slide; means for rotating said control rod relatively to said tooLholder about said rotation/translation axis; and means for translating said control rod relatively to said tool-holder along said rotation/translation axis irrespective of the relative positions of said two threaded members. 2. A device as claimed in claim 1, in which the means for rotating and translating the control rod relatively to the tool-holder include an actuating knob fast with said control rod and accessible from outside the device,

3. A device as claimed in claim 1, in which the means for translating said control rod further include a spring having one end reacting against said tool-holder and the other end reacting against an abutment means fast with said control rod.

4. A device as claimed in claim 1, further including locking means for latching control rod in a predetermined invariable axial position in relation to said toolholder whereby to prevent any axial translation motion of said control rod from such locked position; and unlocking means accessible from outside the device for releasing said control rod.

5. A device as claimed in claim 4, in which said look ing means include balls adapted to engage into an annular groove formed in said tool-holder coaxially with said tool rotation/translation axis, and a thrust member adapted to thrust said balls into said groove; and in which said unlocking means includes a pushbutton accessible from outside the device and adapted to place said thrust member out of contact with said balls. 

1. A device for fashioning a flange on a wall, said wall separating an inner space from an outer space and being beforehand formed with a hole for communicating said inner space with said outer space, said device comprising, in combination a forming tool having an active portion capable of being inserted from said outer space into said inner space through said hole, said tool being rotatable about a geometrical axis substantially merging with the geometrical axis of said hole and being furthermore translatable linearly along the same axis, said forming tool comprising two distinct forming members symmetrically positioned in relation to said tool rotation/translation axis, a slide slidable coaxially with said tool rotation/translation axis, and attachment means for attaching said two forming members to said slide; a toolholder movable coaxially with said rotation/translation axis; attachment means for attaching said tool to said tool-holder and comprising two hinge pins respectively associated to said two forming members and through the agency of which each of said two forming members is hingedly connected to said tool-holder, said two hinge pins being perpendicular to said rotation/translation axis and symmetrically positioned in relation thereto; means for imparting to said tool-holder rotation about and linear translation along said rotation/translation axis; and adjustable means for rectilinearly translating said slide with respect to said tool-holder along the direction of said rotation/translation axis whereby to simultaneously pivot said two forming members about their respective hinge pins and thereby simultaneously vary the angular positions of said two forming members with respect to said tool-holder, said adjustable means including, in combination a control rod coaxial with said tool rotation/translation axis; two mutually engaging threaded members, one of which is fast with said control rod and the other with said slide; means for rotating said control rod relatively to said toolholder about said rotation/translation axis; and means for translating said control rod relatively to said tool-holder along said rotation/translation axis irrespective of the relative positions of said two threaded members.
 2. A device as claimed in claim 1, in which the means for rotating and translating the control rod relatively to the tool-holder include an actuating knob fast with said control rod and accessible from outside the device.
 3. A device as claimed in claim 1, in which the means for translating said control rod further include a spring having one end reacting against said tool-holder and the other end reacting against an abutment means fast with said control rod.
 4. A device as claimed in claim 1, further including locking means for latching control rod in a predetermined invariable axial position in relation to said tool-holder whereby to prevent any axial translation motion of said control rod from such locked position; and unlocking means accessible from outside the device for releasing said control rod.
 5. A device as claimed in claim 4, in which said locking means include balls adapted to engage into an annular groove formed in said tool-holder coaxially with said tool rotation/translation axis, and a thrust member adapted to thrust said balls into said groove; and in which said unlocking means includes a pushbutton accessible from outside the device and adapted to place said thrust member out of contact with said balls. 